1. Field of the Invention
This invention relates to well servicing tools. More particularly, it relates to wireline tools used to finish or repair the interior surface of well casing tubulars.
2. Description of the Related Art including information disclosed under 37 CFR 1.97 and 1.98
A burr is a deformation of metal wherein a raised edge forms on a metal part which has been machined or otherwise formed. It may be present in the form of a fine wire on the edge of a freshly sharpened tool or as a raised portion on a surface, after being struck a blow from an equally hard, or heavy object.
More specifically, burrs are generally unwanted material remaining after a machining operation such as grinding, drilling, milling, or turning. Burr formation in machining accounts for a significant portion of machining costs for manufacturers in America and around the world. Drilling burrs, for example, are common when drilling almost any material.
Deburring tools may be used where the burr from a previous metal-working operation needs to be removed for cosmetic, safety or performance reasons.
FIG. 6 depicts a wellbore 10 of the prior art in formation F. Wellbore 10 comprises casing 12 which has been perforated in production zone P with perforations 40. Fractures 42 in formation F have been created to enhance the flow of hydrocarbon products from formation F into wellbore 10. Also shown in FIG. 6 are polymer sealing balls 44 which may be used to selectively plug perforations 40 in certain regions of the well. In this way, different production zones may be selectively treated e.g. with an acid treatment or a certain proppant. Fluid pressure within wellbore 10 acts to seat balls 44 in perforations 40 thereby preventing the flow of treatment fluid(s) pumped into wellbore 10 from entering production zone P. Certain perforations 40 in casing 12 are shown in the sealed condition with seated balls 44′. After treating a different production zone (or region of the well), fluid pressure within wellbore 10 may be reduced thereby permitting fluids to flow from formation F into the wellbore, dislodging seated balls 44′
It will be appreciated by those skilled in the art that the sealing effectiveness of polymer balls 44 depends, at least in part, on the smoothness of perforations 40. Inasmuch as perforations 40 are typically formed using shaped-charge explosive devices (“perforating guns”), the holes are often rough. Deburring the holes provides a smoother wellbore (which is less disruptive to fluid flow) and also provides a better seat for polymer sealing balls 44.